Whey protein isolate coating and concentration effects on egg shelf life

The influences of three different concentrations (6, 12 and 18%) of whey protein isolate (WPI) coatings on shelf‐life enhancements of the fresh egg quality (weight loss, pH, Haugh unit, yolk index and colors) and the shelf life were evaluated at room temperature. All coated eggs showed lower weight loss than uncoated eggs. Less weight loss (2.46 for 12% WPI and 2.38 for 18% WPI) was observed in WPI‐coated eggs. Haugh units (HU) indicated that coated eggs remained in grade ‘A’ during 3 weeks storage period, whereas uncoated (UC) changed from grade ‘A’ to ‘B’ after 1 week of storage. The HU and yolk‐index (YI) values of all WPI‐coated eggs were significantly higher than those of UC. Among the coated eggs, there were no significant differences in HU, but 12 and 18% WPI coated had higher YI than WPI 6% coated and UC. The albumen pH of the UC eggs was significantly higher than that of coated eggs. Yolk lightness (L*) and (b*); shell (a*) and (b*) of coated eggs were not different from UC after 4 weeks. Performance of WPI coatings depended on the concentration up to 12% but not between 12 and 18%. Results also indicated that WPI coatings served as protective barrier for shelf life of the eggs. Copyright © 2005 Society of Chemical Industry     

Effect of garlic powder on the performance,egg traits and blood parameters of laying hens

This study was conducted to investigate the effects of garlic powder on the performance, egg traits and blood parameters of laying hens. One hundred and sixty‐two SHSY‐type brown layers aged 21 weeks were chosen at random from a large flock. They were allocated to three dietary treatments. Each treatment comprised six replicates of nine layers in groups of three. The diets were supplemented with 0, 5 and 10 g kg^?1 garlic powder. The experimental period lasted 22 weeks. Garlic powder addition did not significantly affect body weight, egg production, feed consumption, feed efficiency, egg shell index, egg breaking strength, egg shell thickness, egg albumen index, egg yolk index, egg Haugh unit, egg yolk weight and serum protein concentration. Egg weight increased (P < 0.01) with garlic powder supplementation. There was a significant (P < 0.01) reduction in egg cholesterol concentration as mg g^?1 yolk when the dietary level of garlic powder was increased from 0 to 10 g kg^?1. Hen serum triglyceride (P < 0.05) and total cholesterol (P < 0.01) concentrations decreased with garlic powder supplementation. This study demonstrated that garlic powder addition increased egg weight and decreased egg yolk cholesterol concentration (mg g^?1 yolk) and serum triglyceride and cholesterol concentrations without adverse effects on performance and egg traits. Copyright © 2006 Society of Chemical Industry     

Cumin seed meal as an alternative to wheat bran in commercial laying hen diets

To evaluate the nutritional significance of cumin seed meal (CSM) as a commercial poultry feedstuff on laying hen performance and quality of laid eggs, an experiment was conducted using 144 (48‐week‐old) laying hens receiving diets containing 0, 25 and 50 g CSM kg^?1 with or without polyethylene glycol (PEG 6000) and xylanase enzyme (Grindazym^? GP 15000) for 9 weeks. Body weight on the first and last days of the experiment and daily egg production and egg weight and weekly feed intake during the first, fifth and ninth weeks of the experiment were recorded. Shell weight, shell thickness, Haugh unit and yolk colour were measured during the last week of the experiment. The results showed that inclusion of CSM in laying hen diets had no negative influence on the parameters measured compared with the control diet (P > 0.05), but enhanced egg yolk colour (P < 0.05). PEG increased the daily feed intake of birds receiving CSM diets (P < 0.01) and tended to enhance daily egg production and egg weight, although not significantly. Grindazym decreased shell weight and thickness of laid eggs (P < 0.05) and tended to increase hen body weight, but had no influence on other parameters measured. The results demonstrated that CSM can be substituted for wheat bran in layer diets at 25 or 50 g kg^?1 dietary inclusion level without any adverse effect on hen performance or egg quality, and might enhance egg yolk colour. In view of the low price of CSM, it could be concluded that inclusion of CSM in the diet might be beneficial to the commercial laying hen industry and reduce the overall cost of egg production. Copyright © 2006 Society of Chemical Industry     

鸡蛋生产环节沙门氏菌检测及洁蛋对蛋品质影响的研究

目的 对鸡蛋生产过程中沙门氏菌污染环节进行研究, 探明规模化蛋鸡养殖场鸡蛋生产中沙门氏菌污染状况和洁蛋效果。方法 选择规模化蛋鸡场一个, 对可能造成鸡蛋沙门氏菌污染的水、饲料、蛋网、传输带等环节的样本进行采样, 并取清洁前后的鸡蛋各60个, 分为两组, 每组中30个蛋用于当天检测, 另外30个, 在室温环境下放置10 d后检测。所有样品经前增菌和选择性增菌后, 提取细菌DNA进行鉴定。结果 水、饲料和清洁后的鸡蛋表面未检出沙门氏菌, 蛋网、传输带、未清洁的鸡蛋表面检出沙门氏菌, 进一步检测表明, 检出的沙门氏菌均不是肠炎沙门氏菌和伤寒沙门氏菌。鸡蛋放置10 d后检测, 未清洁组的蛋白高度和哈氏单位显著低于清洁组的蛋白高度和哈氏单位, 二者均显著低于当天检测的结果, 而各组的蛋壳强度差异均不显著。结论 鸡蛋清洁涂膜处理后可以有效减少蛋壳表面沙门氏菌污染, 并延长鸡蛋的保存时间。     

Hazards with cracked eggs and their relationship to egg shell strength

BACKGROUND: This study examined the relationship between egg shell strength and the prevalence of cracked shells, plus the relationship between egg shell cracks and the presence of bacteria in the albumen of retail eggs. A total of 500 eggs was sampled from five supermarket stores. Each egg was assessed for shell cracks using a candling method. The strength of the shells was assessed using a penetrometer. Bacteria from the egg albumen were recovered on blood agar. RESULTS: The proportion of eggs that were cracked was on average 9%, and at one of the stores it was 17%. Albumen from eggs with gross cracks produced more abundant bacterial growth on blood agar compared to non‐cracked eggs, and contained a higher incidence of Gram negative bacteria. Campylobacter spp. were not recovered from any eggs. The shells in cracked eggs had lower Shore D durometer values indicating that they were physically weaker than non‐cracked eggs. CONCLUSIONS: Weaker shells were more prone to developing cracks, and cracked eggs were more likely to contain bacteria. There were substantial differences between supermarkets in the prevalence of eggs with cracked shells. Copyright © 2008 Society of Chemical Industry     

Inactivation of Salmonella in Shell Eggs by Hot Water Immersion and Its Effect on Quality

Thermal inactivation kinetics of heat resistant strains of Salmonella Enteritidis in shell eggs processed by hot water immersion were determined and the effects of the processing on egg quality were evaluated. Shell eggs were inoculated with a composite of heat resistant Salmonella Enteritidis (SE) strains PT8 C405, 2 (FSIS #OB030832), and 6 (FSIS #OB040159). Eggs were immersed in a circulating hot water bath for various times and temperatures. Come‐up time of the coldest location within the egg was 21 min. SE was reduced by 4.5 log at both hot water immersion treatments of 56.7 C for 60 min and 55.6 °C for 100 min. Decimal reduction times (D‐values) at 54.4, 55.6, and 56.7 °C were 51.8, 14.6, and 9.33 min, respectively. The z‐value was 3.07 °C. Following treatments that resulted in a 4.5 log reduction (56.7 °C/60 min and 55.6 °C/100 min), the surviving population of SE remained static during 4 wk of refrigerated storage. After processing under conditions resulting in 4.5 log reductions, the Haugh unit and albumen height significantly increased (P < 0.01) and yolk index significantly decreased (P < 0.05). The shell dynamic stiffness significantly increased (P < 0.05), while static compression shell strength showed no significant difference (P < 0.05). Vitelline membrane strength significantly increased (P < 0.05); although, no significant difference (P < 0.05) was observed in vitelline membrane elasticity. In summary, the hot water immersion process inactivated heat resistant SE in shell eggs by 4.5 log, but also significantly affected several egg quality characteristics.     

鸡蛋内部品质与其呼吸强度的关系

贮藏期鸡蛋品质的变化与呼吸作用息息相关,为了进一步明确鸡蛋内部品质与其呼吸强度之间的关系,本研究选取同一品种的鸡蛋作为实验样本,利用呼吸测定仪测定鸡蛋的二氧化碳呼吸强度,通过SPSS 19.0软件分别分析鸡蛋哈夫单位、蛋白高度、pH值、黏度、蛋黄指数、蛋黄比例以及蛋黄色度与呼吸强度间的关系。结果表明：鸡蛋哈夫单位、蛋白高度及黏度与呼吸强度之间呈极显著正相关（P＜0.01）;pH值与呼吸强度之间呈极显著负相关（P＜0.01）;蛋黄指数、蛋黄色度与呼吸强度之间呈极显著正相关（P＜0.01）;而蛋黄比例与呼吸强度间相关性较小;此外,pH值与黏度、蛋黄指数、蛋黄色度间均存在极显著负相关（P＜0.01）;黏度与蛋黄指数、蛋黄色度之间呈极显著正相关（P＜0.01）;蛋黄比例与其他参数相关性较小。总之,在鸡蛋内部品质参数中,鸡蛋哈夫单位、蛋白高度、蛋黄指数、pH值、黏度及蛋黄色度对呼吸强度影响较大。     

Deposition of carotenoids in egg yolk by short‐term supplement of coloured carrot (Daucus carota) varieties as forage material for egg‐laying hens

BACKGROUND: Supplying egg‐laying hens with different forage materials may influence egg production and quality. The aim of this study was to examine the short‐term effects of standard feed plus 70 g day^?1 per hen of three coloured carrot varieties (orange, yellow and purple) as forage material in comparison with a standard feed control on egg production, egg yolk colour and deposition of carotenoids in the yolk. RESULTS: Carrot supplementation reduced feed intakes significantly, but not on a dry matter basis. Orange carrot treatment significantly reduced egg mass production, whereas yellow and purple carrot treatments did not differ from the control. Egg and yolk weights of all carrot‐supplemented treatments were significantly lower than those of the control, but yolk percentages were similar. Yolk redness increased significantly in the order control < yellow < orange < purple. A similar trend was seen for yolk yellowness, but yellow and orange carrots reached the same level. Yolk colour and carotenoid contents correlated positively and significantly. In particular, purple carrot treatment increased the yolk content of lutein (>1.5‐fold) and β‐carotene (>100‐fold) compared with the control. CONCLUSION: Supplementing the feed of egg‐laying hens with coloured carrots efficiently increased yolk colour parameters and carotenoid contents, which gives opportunities for improved nutritional value of eggs from forage material‐supplemented hens. Copyright © 2010 Society of Chemical Industry     

Effects of Lactobacillus cultures on performance of laying hens,and total cholesterol,lipid and fatty acid composition of egg yolk

BACKGROUND: The use of antibiotic growth promoters in animal feeds is not approved for laying hens in many countries, and economically feasible biological measures which include probiotics are developed to improve hen performance. The present study investigated the effects of probiotics on hen performance for a 48‐week period and the cholesterol, total lipid and fatty acid composition of egg yolk at 24, 28 and 32 weeks of age. RESULTS: Egg weight of Lactobacillus culture (LC)‐fed hens was significantly (P < 0.05) greater than that of control hens throughout the laying period. From 20 to 44 weeks of age, LC‐fed hens produced a significantly (P < 0.05) lower percentage of small eggs and a higher percentage of large eggs, and from 45 to 68 weeks of age a significantly (P < 0.05) lower percentage of medium eggs and a higher percentage of large and extra‐large eggs than control hens. Significantly (P < 0.05) less cholesterol was found in egg yolks of hens fed LC at 24 and 28 weeks of age, but not at 32 weeks of age. The total lipid content and the fatty acid composition of egg yolks were similar between the treatments at 24, 28 and 32 weeks of age, except for stearic acid (C_{18 : 0}), which was significantly reduced in the egg yolk of LC‐fed hens at 28–32 weeks of age. CONCLUSION: The greatest benefit of LC was in increasing egg weight and improving egg size by influencing a shift from small and medium to large and extra‐large eggs. Copyright © 2008 Society of Chemical Industry     

Effect of salting processes on chemical composition,textural properties and microstructure of duck egg

BACKGROUND: Salted eggs have been produced in Thailand and consumed nationwide. Salted egg can be made by brining eggs in saturated saline or by coating the egg with soil paste mixed with salt. The achievement of salting is generally indicated by the textural development of egg yolk. Yolk property is therefore a prime factor governing consumer acceptability and market demand. The objective of this study was to determine chemical composition, textural properties and microstructure of duck egg obtained from the coating and immersing methods at different salting times. RESULTS: Decreases in moisture content with coincidental increases in salt content in both egg white and yolk were observed during salting, regardless of salting process. However, no difference in salt content was noticeable in yolks (P > 0.05). The paste coating method tended to yield greater oil exudation of egg yolk than the immersing method. Maximum transition temperature (T_max) of egg proteins and thiobarbituric acid‐reactive substance (TBARS) value in yolk increased with increasing salting time. A similar hardening ratio of yolk was observed in both processes. Higher hardness and adhesiveness were found in yolk with the paste coating method, whereas greater fracturability, springiness, gumminess and chewiness were observed with the immersing method. Nevertheless, both processes rendered the yolk with similar cohesiveness. Yolk granules were aligned closely when salting proceeded, irrespective of salting process. CONCLUSION: Dehydration and release of lipids in egg yolk increased with increasing salting time and were more pronounced with the paste coating method. Therefore salting processes affected the properties of salted eggs. Copyright © 2009 Society of Chemical Industry     

Effects of dietary taurine on egg production,egg quality and cholesterol levels in Japanese quail

BACKGROUND: Taurine is a semi‐essential amino acid and has many biological properties. The objective of this study was to determine the effect of dietary supplementation with taurine on egg production, egg quality, and cholesterol level in serum and egg yolk of quails. A total of 108 quails aged 6 weeks were randomly allocated to three dietary treatments. Each treatment consisted of four replicates of nine quails. The diets were supplemented with 0, 100, and 500 mg kg^?1 of taurine for 8 weeks. RESULTS: Dietary 500 mg kg^?1 taurine significantly affected egg production rate and feed conversion ratio, but had no significant effects on body weight gain, feed consumption, or egg weight. Dietary taurine had no significant effect on egg quality parameters studied. Serum triglyceride concentration was reduced significantly with supplementation of taurine at 100 and 500 mg kg^?1. Egg yolk cholesterol content was reduced significantly, and the contents of serum taurine and egg yolk taurine were increased significantly with taurine supplementation at 500 mg kg^?1. CONCLUSION: Results of the present study indicated that adding 500 mg kg^?1 taurine reduced yolk cholesterol concentration and increased yolk taurine content without adverse effects on performance and egg quality of laying quails. Copyright © 2010 Society of Chemical Industry     

Effect of various refrigeration temperatures on quality of shell eggs

BACKGROUND: The objective of this study was to evaluate the effects of low storage temperatures on shell egg quality. RESULTS: Approximately 2100 shell eggs were collected and stored at ? 1.1, 0.6, 2.2, 3.9, 5.6 and 7.2 °C for up to 4 weeks. Eighteen eggs at each storage temperature were evaluated after 0, 2, 7, 14, 21 and 28 days of storage. Haugh units (HU), yolk index (YI), albumen pH (pHA), yolk pH (pHY) and angel food cake density (CD) were measured. Shell egg quality tended to be preserved better at below 2.2 °C, as high HU and YI values relative to eggs stored at 7.2 °C were determined on day 28. However, storage at ? 1.1 °C tended to cause the opposite effect, especially highly declined HU values over time. Significantly different HU values of shell eggs were measured after 14 days of storage, with eggs stored at 0.6 and 2.2 °C having the highest HU values, 80.42 and 77.97 respectively. CONCLUSION: A lower temperature limit for shell egg storage could be established between 0.6 and 2.2 °C, as both temperatures showed the highest HU values, 77.88 and 77.60 respectively, after 28 days of storage. Copyright © 2011 Society of Chemical Industry     

The influence of different single dietary sources on moult induction in laying hens

An investigation was carried out to assess the possibility of using single dietary sources as alternatives to feed deprivation for the induction of moult in commercial laying hens. The study involved six dietary groups of 29 laying hens: unmoulted, dried tomato pomace, alfalfa meal, rice bran, cumin seed meal and feed withdrawal. The birds received the above diets during the moulting period (11 days), and body weight loss and ovary weight regression were measured. Post‐moult production parameters (number of eggs produced per hen per day, egg weight, shell weight, yolk colour and Haugh unit) were measured for 12 weeks. Results showed that all dietary sources were as effective as feed withdrawal in causing ovary weight regression in birds. Birds provided with tomato pomace or alfalfa showed lower weight losses than feed‐deprived birds at the end of the moulting period. Hens moulted by tomato pomace or alfalfa exhibited post‐moult levels of egg production over a 12 week period that were superior to those of hens moulted by feed withdrawal. Post‐moult eggs laid by hens moulted by all dietary sources were of comparable quality to eggs from feed‐deprived hens and superior to those from unmoulted hens. As fibrous feeds with low metabolisable energy and an appreciable amount of protein, dried tomato pomace and alfalfa meal may be fed to hens on an ad libitum basis for effective moult induction while reducing the stress of severe starvation and retaining comparable egg quality and production. Copyright © 2007 Society of Chemical Industry     

贮藏条件与禽蛋品质的相关性研究

为了比较不同贮藏条件对禽蛋品质的影响,将鸡蛋、鸭蛋和鹅蛋置于5、10、20、30℃贮藏30d,分析3种禽蛋品质变化与贮藏条件相关性规律。结果表明:贮藏温度对禽蛋品质的影响显著,高温贮藏加速禽蛋品质下降;禽蛋品质随贮藏时间延长而下降;除哈夫单位,3种禽蛋品质可以用相同品质指标来衡量。拟合方程的判定系数表明,贮藏过程中失重率和整蛋pH变化可以用零级反应动力学方程表征,哈夫单位和蛋黄指数变化规律可以用一级反应动力学方程表征。品质变化动力学级数与禽蛋品种无关,不同种类禽蛋在贮藏过程中品质变化规律基本相似。     

不同品种鲜蛋品质差异分析

目的探究褐壳蛋、粉壳蛋和白壳蛋3种类型鸡蛋的品质差异以及对于蛋粉加工的潜在影响。方法选用京红1号、京粉1号和京白1号所产的褐壳蛋、粉壳蛋和白壳蛋作为试验对象,对37周龄和51周龄蛋鸡所产3种类型鸡蛋的蛋品质进行分析比较。结果 37周龄和51周龄的白壳蛋蛋壳厚度、蛋壳比例和蛋壳强度均显著低于其他2个类型鸡蛋(P0.05);37周龄时3种类型鸡蛋的蛋黄水分含量没有显著性差异(P0.05);白壳蛋蛋清水分含量以及总水分含量均较其他2个类型鸡蛋要低。37周龄时褐壳蛋的蛋黄蛋白质和脂肪含量均显著高于其他2个品种,白壳蛋次之,粉壳蛋最低。37周龄时白壳蛋的蛋清蛋白质含量显著低于其他2个品种。由于蛋清中脂肪含量极少,本试验不予考虑。结论褐壳蛋加工成蛋粉后具有更好的营养价值,而白壳蛋可以提高蛋粉加工的产量。     

Effect of probiotic (Lactobacillus sporogenes) feeding on egg production and quality,yolk cholesterol and humoral immune response of White Leghorn layer breeders

The effect of probiotic (Lactobacillus sporogenes) feeding on egg production and quality, yolk cholesterol and humoral immune response of White Leghorn (WL) layer breeders was studied. WL layer breeders (24 weeks) were randomly distributed into three groups of 28 each and were housed in individual California type cages. Considering one bird (individual feeding) as a replicate, 28 such replicates were randomly allotted to one of the three dietary treatments: basal (control) or basal with probiotic supplementation at a rate of 100 or 150 mg kg^?1 feed. The probiotic used in the study was a commercial preparation containing L. sporogenes with 6000 million spores g^?1 of the product. Dietary supplementation of L. sporogenes at 100 mg (6 × 10⁸ spore) kg^?1 diet significantly increased egg production and feed efficiency. However, body weight gain, feed intake, egg weight, specific gravity and Haugh unit was not influenced by probiotic feeding. The eggshell breaking strength, shell weight and shell thickness increased significantly by feeding 100 mg probiotic kg^?1 diet. The serum concentration of calcium and protein increased, and that of cholesterol decreased by L. sporogenes supplementation. The yolk cholesterol followed the same trend of serum cholesterol. Feeding of L. sporogenes significantly enhanced antibody production. No difference in antibody production could, however, noticed between the levels (100 or 150 mg) of probiotic. It is concluded that feeding of L. sporogenes at 100 mg (6 × 10⁸ spore) kg^?1 diet significantly enhanced the egg production, shell quality and humoral immune response of WL layer breeders during 25–40 weeks of age. Copyright © 2007 Society of Chemical Industry     

Fatty acid profile and cholesterol content of egg yolk from chickens fed diets supplemented with purslane (Portulaca oleracea L.)

BACKGROUND: The aim of the present study was to evaluate the effects of purslane on egg production, egg weight, feed efficiency, yolk fatty acid composition, and egg cholesterol content in laying hens. MATERIAL AND METHODS: Sixty 80‐week‐old layers were allocated randomly to receive diets supplemented with 0 (control), 10 g kg^?1 or 20 g kg^?1 dried purslane for 84 days. Egg weights and egg production in the groups were recorded daily, whereas feed intake was measured weekly. RESULTS: Diet supplemented with 20 g kg^?1 purslane significantly decreased body weight of the chickens compared to the control. Inclusion of purslane at the level of 10 g kg^?1 or 20 g kg^?1 into the diet significantly (P < 0.05) improved egg weight compared to the control. Chickens fed the diet including 20 g kg^?1 purslane had a significantly (P < 0.05) higher egg production and improved feed efficiency compared to the control. Cholesterol content of eggs from the hens fed 0, 10 or 20 g kg^?1 did not differ and was 10.45, 9.51 or 9.51 mg g^?1 dried egg yolk, respectively. Inclusion of purslane at the level of 20 g kg^?1 into the diet significantly (P < 0.05) increased ω‐3 fatty acids such as C18:3(ω‐3) and C22:6(ω‐3). The ratio of ω‐6 to ω‐3 also was significantly (P < 0.05) lower in the eggs from chickens fed 10 g kg^?1 or 20 g kg^?1 purslane supplemented diets compared to the control. CONCLUSION: This study showed that adding dried purslane to the diet of laying hens significantly increased egg production and egg weights although there was no reduction in the egg cholesterol concentration. This study also showed that inclusion of purslane into diet enriched eggs with ω‐3 fatty acids and decreased the ratio of ω‐6/ω‐3 in the yolk. Copyright © 2010 Society of Chemical Industry     

Effects of dietary black cumin seed (Nigella sativa L.) on performance,egg traits,egg cholesterol content and egg yolk fatty acid composition in laying hens

BACKGROUND: The objective of this study was to determine the effects of dietary black cumin seed on performance, egg traits, egg cholesterol content and egg yolk fatty acid composition in laying hens during a 12 week period. For this purpose a total of 160 Lohmann Brown laying hens 36 weeks of age were allocated to four dietary treatments with one control group and three treatment groups. Black cumin seed (Nigella sativa L.) was used at the level of 5, 10 and 15 g kg^?1 in the diets of the first, second and third treatment groups, respectively. RESULTS: Dietary treatments did not significantly affect body weight, feed intake, egg production, egg quality characteristics and blood parameters. Diets containing 10 and 15 g kg^?1 black cumin seed increased egg weight (P < 0.01), improved feed efficiency (P < 0.01) and decreased egg yolk cholesterol, saturated fatty acids (% of total fatty acid methyl esters) and the ratio of saturated to unsaturated fatty acids (P < 0.05) compared to the diet of control group. CONCLUSION: Dietary black cumin seed at the level of 10 and 15 g kg^?1 had beneficial effects on egg weight, feed efficiency, egg cholesterol content and egg yolk fatty acid composition. Therefore it can be used at the level of 10 and 15 g kg^?1 in the diets of laying hens. Copyright © 2009 Society of Chemical Industry     

Chitosan coating minimises eggshell breakage and improves egg quality

The interior quality of eggs, shell impact strength, and consumer perception of eggs coated with chitosan containing an organic acid (acetic, lactic and propionic) were evaluated. Uncoated eggs had the highest albumen pH and lowest albumen viscosity. The viscosity of eggs coated with chitosan and lactic or propionic acids were the highest. Chitosan coating also improved shell strength with chitosan + lactic acid being the best coating in this regard. The colour of shell and yolk as measured by lightness (L*), a*, b*, chroma and hue of coated and uncoated eggs were not significantly different but the difference was detected in the colour of albumen, which is an effective indication of freshness and egg quality. Based on sensory evaluation, consumers could not differentiate coated eggs from uncoated eggs; thus the general acceptability of the coated eggs was the same as uncoated eggs. This study shows a great potential of using chitosan and lactic acid mixture as a coating material for egg coating to extend the shelf life. It has no effect on consumer acceptability of the product. Copyright © 2007 Society of Chemical Industry     

Effects of dietary yeast autolysate (Saccharomyces cerevisiae) on performance,egg traits,egg cholesterol content,egg yolk fatty acid composition and humoral immune response of laying hens

BACKGROUND: The objective of this study was to determine the effects of dietary yeast autolysate on performance, egg traits, egg cholesterol content, egg yolk fatty acid composition, lipid oxidation of egg yolk, some blood parameters and humoral immune response of laying hens during a 16 week period. A total of 225 Hyline Brown laying hens, 22 weeks of age, were allocated equally to one control group and four treatment groups. Yeast autolysate (Saccharomyces cerevisiae, InteWall) was used at levels of 1, 2, 3 and 4 g kg^?1 in the diets of the first, second, third and fourth treatment groups respectively. RESULTS: Dietary treatments did not significantly affect body weight, feed intake and egg traits. Yeast autolysate supplementation increased egg production (P < 0.001) and egg weight (P < 0.001) and improved feed efficiency (P < 0.05). Yeast autolysate at levels of 2, 3 and 4 g kg^?1 decreased egg yolk cholesterol level as mg g^?1 yolk (P < 0.01) and blood serum levels of cholesterol and triglyceride (P < 0.05) and increased antibody titres to sheep red blood cells (P < 0.01). Total saturated fatty acids and the ratio of saturated/unsaturated fatty acids increased (P < 0.01) and total monounsaturated fatty acids (P < 0.001) decreased with yeast autolysate supplementation. CONCLUSION: Dietary yeast autolysate at levels of 2, 3 and 4 g kg^?1 had beneficial effects on performance, egg cholesterol content and humoral immune response. It is concluded that 2 g kg^?1 yeast autolysate will be enough to have beneficial effects in laying hens. Copyright © 2010 Society of Chemical Industry